Pseudotumor cerebri

Abstract

Pseudotumor cerebri (PTC) is a syndrome of increased intracranial pressure without hydrocephalus or mass lesion and with normal cerebrospinal fluid (CSF) composition. Although often considered to be "idiopathic," detailed investigation has revealed a high incidence of venous outflow abnormalities in PTC syndrome patients. The thought that elevated intracranial venous sinus pressure is a "universal mechanism" for PTC syndrome of varying etiologies has been called into question by a study indicating that the increased venous pressure in idiopathic PTC patients is caused by the elevated intracranial pressure and not the reverse, suggesting that "the chicken is the CSF pressure elevation and the egg is the venous sinus pressure elevation." Vitamin A toxicity may play a role in the pathogenesis of idiopathic PTC. The treatment of PTC has two major goals: the alleviation of symptoms and preservation of visual function. When medical therapy fails or when visual dysfunction deteriorates, surgical therapies for PTC should be considered. The two main procedures performed include lumboperitoneal shunt and optic nerve sheath fenestration. Because of the association of PTC with venous sinus hypertension, some authors are considering venous sinus stenting for refractory cases of PTC. It is still unclear if primary treatment of the observed venous stenosis benefits patients with idiopathic PTC. This should be no surprise, as it is not certain whether the stenoses are the cause or the result of idiopathic PTC.

Pseudotumor Cerebri: Brief Review of Clinical Syndrome and Imaging Findings

“…6 Even if it is assumed that venous stenosis exists in PTC, there is controversy as to whether venous stenosis and elevated venous pressure are due to elevated ICP or constitute the proximal cause of PTC. [14][15][16] The first explanation is an application of the Monroe-Kellie doctrine: Expansion of the brain within a fixed space will lead to the compression of venous sinuses, assuming that these are compressible structures, to vent CSF during systole when ICP increases. 17 One cadaveric study suggested that the stenosis of the transverse sinus observed in IIH might be due to the presence of a large septum within the venous sinus.…”

“…15 A small or absent bony groove in the occiput in conjunction with the compressible nature of the transverse sinus makes this structure vulnerable to tapering with increased ICP. 65 This particular imaging finding is more frequently noticed on MR venography studies, which are discussed at more length below.…”

“…22 Acetazolamide is historically the most commonly used medication to treat PTC, but topiramate has been shown to have equal effect as a result of partial carbonic anhydraseϪinhibition activity augmented by beneficial analgesic action against headaches and weight loss as a fortuitous side effect. 15,26,48 Corticosteroids may result in temporary remission of PTC, but the risks of chronic steroid use in already obese patients preclude their use. Some clinicians advocate the use of corticosteroids in patients with severe headache, acute papilledema, and very high CSF pressure.…”

“…Some clinicians advocate the use of corticosteroids in patients with severe headache, acute papilledema, and very high CSF pressure. 15,49 Therapeutic lumbar puncture is another common treatment method and addresses the issue of elevated CSF pressure directly by reducing it immediately; 1 older study suggests that the effects are short-lived, with a return to initial pressure within just Ͼ1 an hour. 50 There is little published evidence comparing lumbar puncture with medication or other treatment modalities.…”

Idiopathic Intracranial Hypertension in Pregnancy Treated with Serial Lumbar Punctures

“…Surgical procedures like optic nerve sheath fenestration and lumboperitoneal or ventriculoperitoneal shunting may improve the venous drainage from the brain [6,8,15]. Since IIH is associated with venous sinus hypertension, venous sinus stenting has also been proposed for unresponsive cases [16]. Of these procedures, optic nerve sheath fenestration requires less anesthesia time which is one of the factors that has to be considered in pregnant women [3].…”